This invention relates to new and useful improvements in pallet dismantling machines and to a cutter head assembly therefor.
Wooden pallets are extensively used for stacking products to be transported or stored. Since considerable lumber is used in construction of the pallets, damaged pallets frequently are repaired rather than discarded. Power devices have heretofore been patented for dismantling the pallets, for example, devices shown in U.S. Pat. Nos. 3,869,780, 4,320,570, and 4,945,626. In order for a pallet dismantling machine to be economically feasible, it must operate with such efficiency as to make its use a substantial improvement over hand dismantling or repair. This efficiency must be adequate to the extent that whole or partial dismantling of the pallet is a speedy and low effort operation. Also pallet dismantling machines must be rugged and reliable in use whereby to be substantially free of down time due to repair or maintenance.
In the construction of pallets, they comprise a plurality of upper and lower deck boards nailed transversely to two or more stringers or longitudinally aligned blocks. The pallet structure requires a spacing of the stringers or blocks such that the pallet can receive the forks of a lift truck. Aside from that requirement, pallets are of many different sizes and with different spacing between the stringers or blocks. A single head pallet dismantling machine is not materially affected by different pallet dimensions since the pallets must be run through as many times as there are stringers. Such is a slow process because the pallet has to be returned for cutting the nails of each succeeding stringer or row of blocks.
This problem has been recognized and U.S. Pat. No. 4,320,570 proposes a multiple head pallet dismantling machine that employs lateral adjusting drive for the multiple head supports. This is accomplished by mounting the heads on trolleys and the trolleys are laterally adjusted by hydraulic cylinder means on the machine frame. This type of structure is complex and expensive and financially not available to small operators.
Another problem in dismantling pallets by forcing the nails through free running cutting discs is the violent forces that act on the machine parts and on the pallets as a result of power driven pusher means. Machines such as shown in U.S. Pat. No. 4,320,570 and U.S. Pat. No. 4,945,626 support cutter heads on elongated cantilevered arms. This elongated arm arrangement makes the cutter heads and pallets vulnerable to damage due to the difficulty of properly moving pallets into the cutter head in efficient straight line receptive travel. Any material misalignment between the path of travel of the pallet and the cutter heads can cause severe damage to the heads and to the pallets. Prior machines also do not provide an efficient method of clearing the machine of broken pallet parts.